First-trimester bleeding and pregnancy outcome in singletons after assisted reproduction

BACKGROUND: First-trimester bleeding is frequent in assisted reproductive technique (ART) pregnancies. It is unknown whether first-trimester bleeding, if not ending in a spontaneous abortion, negatively influences further pregnancy outcome in ART in singletons. METHODS: Data were obtained from our ART database (1993-2002), with 1432 singleton ongoing pregnancies being included in this study. The outcome measures-second-trimester and third-trimester bleeding, preterm contraction rates, pregnancy duration, birthweight, Caesarean section rates, intrauterine growth retardation (IUGR), preterm prelabour rupture of membranes (P-PROM), neonatal intensive care unit (NICU) admission and perinatal mortality-were compared in the groups with and without first-trimester bleeding. RESULTS: Significantly more singleton pregnancies resulted from a vanishing twin in the group with first-trimester bleeding (8.7%) than in the controls (4.0%). A correlation was found between the incidence of first-trimester bleeding and the number of embryos transferred. First-trimester bleeding led to increased second-trimester [odds ratio (OR) = 4.56; confidence interval (CI) = 2.76-7.56] and third-trimester bleeding rates (OR = 2.85; CI = 1.42-5.73), P-PROM (OR = 2.44; CI = 1.38-4.31), preterm contractions (OR = 2.27; CI = 1.48-3.47) and NICU admissions (OR = 1.75; CI = 1.21-2.54). First-trimester bleeding increased the risk for preterm birth (OR = 1.64; CI = 1.05-2.55) and extreme preterm birth (OR = 3.05; CI = 1.12-8.31). CONCLUSIONS: First-trimester bleeding in an ongoing singleton pregnancy following ART increases the risk for pregnancy complications. The association between first-trimester bleeding, the number of embryos transferred and adverse pregnancy outcome provides a further argument in favour of single-embryo transfer.